This invention relates to air handling systems for use in a building in order to supply air to the interior of a building and, in particular, to such a system employing an axial fan unit.
A number of different air handling systems are known for providing conditioned air to a building""s interior. These systems can vary depending upon the size of and requirements of the building. They also differ on the basis of the perceived requirements for heating and cooling in the building. Particularly in systems designed for larger buildings, a concern of the building owner and of the users of the building is that the air handling system be not only efficient for the delivery of conditioned air to each floor of the building but also relatively quiet in its operation.
Relatively sophisticated air handling systems for multi-storey buildings are already known in the heating and air conditioning industry. For example, it is already known to provide a relatively large axial fan on a lower floor of a multi-storey building in order to deliver the required conditioned air through a system of air ducts to the various floors of the building. In order to reduce the sound levels that are produced by the operation of the fan, the fan inlet can be mounted adjacent an inlet attenuator which directs incoming air into the inlet side of the fan. There can also be an outlet attenuator mounted adjacent the outlet side of the fan and connected to one or more air delivery ducts. Both of these attenuators can have exterior walls and specially designed interior walls with sound attenuating material arranged between the interior and exterior walls. One perceived difficulty with these known system is that they generally require a reasonably large room set aside on the lower floor for the air handling system, including the attenuators and, with such systems, difficulties can be encountered in controlling the conditioned air delivered to each floor of the multi-storey building and in modifying the air delivery system when changes, are made to the layout of one or more of the floors of the building.
In U.S. Pat. No. 4,418,788 issued Dec. 6, 1983 to Mitco Corporation there is disclosed a composite branch take-off and silencer for an air distribution system. This take-off unit includes two series-coupled sections including a static pressure regain section and a channel section adapted for coupling an input duct to an output duct and branch ducts. With this unit, the input section is located adjacent the axial fan which is generally located at the bottom end while the channel section which is coupled to a main duct for the delivery of air is located in the upper half of the unit. Sound absorbing material is used at several locations in the unit to reduce the amount of sound passing through the unit and into the air ducts.
More recent U.S. Pat. No. 4,874,127 issued Oct. 17, 1989 to W. R. Collier describes a multi-level access flooring system with a working area floor and at least one intermediate floor. A horizontal plenum is formed between an intermediate floor and the building floor. An HVAC unit is mounted on an elevated top floor and this unit has an axial fan and an air outlet located at the bottom thereof. Just above the outlet are arranged evaporator coils. Air from the room enters the HVAC unit through a top grill. As there is no provision for reducing the sound levels emanating from the axial fan, it appears that the climate control system described in this patent specification would be relatively noisy. There is also no provision in this system for mixing fresh air with return air before it is passed through the HVAC unit and delivered to the air distribution plenum and the air outlets.
U.S. Pat. No. 4,646,966 issued Mar. 3, 1987 to Argon Corp. teaches a personalized air conditioning system which employs an air plenum formed by an elevated floor of the building. Air rises from the floor space into an air distribution system which includes an upstanding passageway or column that has upright sidewalls. A small fan is mounted in the column as is an air valve which apparently regulates the air passing upwardly in the column. A plurality of air outlets are provided near the top of the column and are adjustable.
It is an object of the present invention to provide an efficient air handling system that can be provided on each floor of a building, particularly a high-rise building, in order to supply air to the interior.
It is a further object of the present invention to provide a novel air handling system for use in a building having an elevated floor assembly mounted on a principal floor of the building, this assembly including a working area floor which lies above the principal floor so as to provide an air plenum.
It is another object of the present invention to provide an air handling system for use in a building, the system including an air outlet section with a lowermost air outlet, an axial fan unit and an air inlet section that is mounted above the axial fan unit and that has an air mixing chamber arranged to receive airflows entering through air inlet openings.
According to one aspect of the invention, an air handling system for use in a building in order to supply air to the interior thereof comprises, in combination, an elevated floor assembly for mounting on a principal floor of the building, an outlet attenuator for mounting on this principal floor, an axial fan unit mounted above the outlet attenuator, and an inlet attenuator section mounted above the axial fan unit. The floor assembly includes a working area floor which in use lies above and is spaced apart from the principal floor so as to provide an air plenum between the principal floor and the working area floor. The outlet attenuator is adapted to extend upwardly through the working area floor. This attenuator includes an exterior outlet housing having a lower air inlet in the top thereof and a lowermost air outlet in at least one vertical side thereof. The lowermost air outlet is connected to the air plenum during use of the system and is connected to the lower air inlet by a lower air flow passageway defined by interior walls of the attenuator. The outlet attenuator further includes sound absorbing material contained in the housing that extends to and is covered by the interior walls. The axial fan unit is capable of providing downward air flow into the lower air inlet of the outlet attenuator. The inlet attenuator extends upwardly to a ceiling of the building during use of the system. This attenuator includes an exterior inlet housing having an upper air inlet in an upper region thereof and a bottom air outlet in a bottom side thereof. The bottom air outlet is connected to a top inlet of the axial fan unit. The inlet attenuator section further includes sound absorbing material contained in the inlet housing and interior walls forming an upper airflow passageway extending from the upper air inlet to the bottom air outlet.
Preferably, the inlet attenuator section includes air filter panels mounted in the inlet housing and arranged so that all airflow through the upper airflow passageway during use of this system is required to flow through the air filter panels.
According to another aspect of the invention, an air handling system for use in a multi-storey building in order to supply air to a level of the building comprises an outlet attenuator adapted for mounting on a floor of the building, a fan unit mounted above the outlet attenuator and a fan inlet section mounted above the fan unit. The outlet attenuator includes an exterior outlet housing having an air inlet in the top thereof and a lowermost air outlet in at least one vertical side thereof. The air inlet and the air outlet are connected by a lower airflow passageway defined by interior walls. The outlet attenuator further includes sound absorbing material which is contained in the housing and extends to and is covered by the interior walls. The fan unit is capable of providing downward air flow into the air inlet of the outlet attenuator. The fan inlet section extends upwardly from the fan unit and includes an exterior inlet housing with a bottom air outlet in a bottom end thereof and an upper airflow passageway that extends downwardly to the bottom air outlet. The bottom air outlet is positioned directly above the air flow inlet of the fan unit.
Preferably the fan inlet section is a sound attenuator and contains sound absorbing material positioned behind perforated interior walls. In a particularly preferred embodiment, the fan inlet section includes a central elongate airflow member mounted centrally in the upper airflow passageway and having a vertical longitudinal axis. This airflow member also contains sound absorbing material.
According to another aspect of the invention, an air handling system for use in building in order to supply an air mixture to the building comprises, in combination, an air outlet and sound attenuator section adapted for mounting on a floor of the building, a fan unit mountable above the air outlet section, and an air inlet and sound attenuator section mounted above the fan unit. The outlet section includes an outlet housing containing sound absorbing material and a lower airflow passageway extending vertically through the outlet housing to a lowermost air outlet located in at least one vertical side thereof. The fan unit is capable of providing downward airflow into the lower airflow passageway. The air inlet and sound attenuator section includes an inlet housing with a round bottom air outlet in the bottom end thereof and an upper airflow passageway that tapers inwardly in a downwards direction and extends downwardly to the bottom air outlet. The upper airflow passageway is surrounded on vertically extending sides thereof with sound absorbing material. The upper airflow passageway is connected so as to deliver a mixed airflow to an inlet of the fan unit. The inlet housing has first and second air inlet openings formed in an upper section thereof. The first air inlet opening is adapted to receive fresh incoming air and at least the second air inlet opening is adapted to receive return air from the building. During use of the system, the fresh incoming air and the return air are mixed in the air inlet and sound attenuator section.
According to still another aspect of the invention, an air handling system for use in a building in order to supply treated air to the building comprises an air outlet and sound attenuator section adapted for mounting on a floor of the building and including an outlet housing containing sound absorbing material and having a lower airflow passageway extending vertically through the outlet housing to a lowermost air outlet located in at least one vertical side thereof; a fan unit mountable above the air outlet section and capable of providing downward airflow into the lower airflow passageway, and an air inlet and sound attenuator section mounted above the fan unit and including an inlet housing. This housing has a round bottom air outlet in a bottom end thereof and an upper airflow passageway that tapers inwardly in a downwards direction and that extends downwardly to the bottom air outlet. The upper airflow passage is surrounded on vertically extending sides thereof with sound absorbing material. An upper section of the inlet housing has an air inlet opening provided in two or more of the vertically extending sides. The upper airflow passageway is divided into at least two smaller passageways, that extend from the air inlet opening to the bottom air outlet, by means of a substantially conical divider wall which is substantially coaxial with the upper airflow passageway. There is also at least one heat exchanging coil unit mounted in the air inlet and sound attenuator section for heating or cooling at least a portion of the airflow entering the system through the air inlet opening.
Further features and advantages will become apparent from the following detailed description taken in conjunction with the accompanying drawings.